The state of the art in electro-optic (EO) systems is based upon the commercial convention of rectilinear FPAs using detector materials matched to the spectral region of interest. Conventional optics designs are generally circular for simplicity of production and optical performance considerations. Optical materials must have acceptable transmission in the spectral region of interest. A simple EO imaging system consists of an objective lens assembly, FPA, Read Out Integrated Circuit (ROIC), support electronics with power source(s), display drivers, display, and eyepiece lens assembly. As shown in FIG. 1, an object 110 in image space is projected onto an objective lens assembly 120, which focuses it onto a rectilinear focal plane array 130. A readout integrated circuit (ROIC) 140 with its support electronics and display drivers reads out the rectilinear focal plane array signals to a rectilinear display 150 which projects a reconstructed image of said object 110 onto an eyepiece lens assembly 160 for observer's viewing 170.
If a square peg needs to fit into a round hole, then the peg needs to be relatively smaller or the hole needs to be relatively larger; in either case, resources are being discarded. Analogously, in the EO system implementation realm, potential system performance is being compromised by a loss of pixel count as related to available optical area with surrounding optical performance potential not impinging on active pixels (see FIG. 2). Conventional rectilinear approaches to EO systems are based upon standard commercial products, such as televisions and computers, and have evolved into ever increasing pixel counts and aspect ratios. Using existing or future rectilinear approaches to integrate compact EO systems limits performance potential and will become more difficult as the demand for performance improvements and resolution increases.
The state of the art FPA and display technologies for compact EO imager systems are rectilinear, generally on the order of 1K×1K or 2K×1K pixel counts, with aspect ratios of either 4:3 (1280×1024) or 16:9 (1920×1200); flat Panel Displays have evolved in kind. Most systems operate at either 30 or 60 frames per second (fps or Hz) with interlaced or progressively scanned approaches to the FPA and associated display. Nominally, an EO imaging system with 1K pixels, forty (40) degree Field of View, and unity magnification would provide resolution of approximately 0.9 cycles/milliradian, or Snellen Acuity of approximately 20/40; average human vision is over a factor of two better at conventionally 20/20. Resolution requires improvement, with increased pixel counts and associated optical performance, to achieve normal human vision performance.
Processing capability and associated memory requirements for EO systems continue to increase, for simply reading the sensor data, as pixel counts and frame rates increase. In addition to the processing burden, IP algorithms for EO systems are increasingly becoming the standard for performance improvements concerning aberration control, edge enhancement, pixel interpolation, electronic zooming, frame integrations/averages, moving target indication, or any other chosen feature. System Size, Weight, And Power (SWAP) performance are all compromised by increasing processing demands.